Automatic circuit breaker



' y 1951 F. J. M. THEUNISSEN 2,551,303

AUTOMATIC CIRCUIT BREAKER Filed Dec. 3, 1945 20 46 49 a9 48 fix I 26'4.9 i i 4 50 4a 40 a Z 21 43 35 29 25L 5? o 53 32a U 32 [MentorfkA/vgozs 12 40 Mm: 795M535 4 fgf,

Patented May 1, 1951 AUTOMATIC CIRCUIT BREAKER Francois Jean MarieTheunissen, Brussels, Belgium Application December 3, 1945, Serial No.632,442 In Belgium October 17, 1944 Section 1, Public Law 690, August 8,1946 Patent expires October 17, 1964 6 Claims.

My invention relates to circuit-breakers.

My copcnding patent application No. 632,441 filed December 3, 1945,concerns an automatic circuit breaker provided with an electro-magnetthrough which the current passes, and the movable armature of whichactuates means for liberating (by pawl, toggle, etc.) the movablecontact, when an overload current sufficient to attract the saidarmature passes through the apparatus, said circuit breaker beingessentially characterised by the fact that the said movable armatureacts directly on the movable contact, independently of the liberatingmeans actuated by said armature. By the direct action on the movablecontact, must be understood both action on the contact and on itssupport, so long as the impulse of the armature is transmitted to themovable contact, without involving the liberating means.

The present improvements relate to modifications and improvements in thesaid circuit breaker, in particular for the purpose of furtheraccelerating the opening of the circuit in case of a very heavy overloador of a short-circuit.

One of said improvements consists in that the electro-magnet is providedwith an auxiliary armature which acts positively on the movable contact,independently of the main armature and as soon as the movable contacthas been released by the liberating means by the action of thelectro-magnet.

The auxiliary armature is advantageously formed by a part of the memberserving to transmit the impulse of the main armature to the movablecontact, which member can act on the support of the movable contact orcan itself form the support of the movable contact. The main armaturecan, in particular, be slidably mounted about the said member which isprovided with a stop on which the main armature is adapted to act afterhaving released the liberating means.

The provision or" this auxiliary armature has enabled the speed ofopening of the circuit to be further increased, since said auxiliaryarmature is directly afiected by the magnetic flux which should causethe release, and since it is therefore ready to act immediately on themovable contact, as soon as the latter is released, so that theauxiliary armature imparts without any delay a considerable accelerationto the movable contact. If said movable contact had any tendency toadhere to the fixed contact, it would be sharply pulled away from sameby the subsequent direct action of the main armature on the movablecontact or its support.

Other particularities and advantages of the invention will becomeapparent from the description of a few examples of constructions, whichis given hereinafter with reference to the accompanying diagrammaticaldrawing, in which:

Figures 1, 2 and 4 show three variants of construction of a circuitbreaker according to the invention, in the position in which the currentflows, and

Figures 3 and 5 show partial views of the circuit breakers according toFigures 2 and 4, immediately after tripping.

In the case of Figure 1, the movable contact 2 is carried by a beam 3pivoting about a fixed point 3a and subjected, at 31) to the action of aspring 4 which is attached to a second beam 5 pivoting about the fixedpoint 5a. The arrangement is such that, in the engaged positionillustrated in the drawing, the line of action of the spring 4 passesbetween the points 3a and 5a and presses the contact 2 against the fixedcontact 6. The beam 5 is held in this position by a pawl I, which can beactuated through the intermediary of an arm [0, against the action of aspring la. The current flows through the beam 3, the contacts 2, 6, thetripping coil 9 and a time relay formed by a bimetallic strip 8. When amoderate overload occurs, said strip acts on the arm III which releasesthe pawl I and enables the beam -5 to move in the direction of the arrowX by the action of the spring 6 until it contacts a suitable stop 52)and the line of action of said spring passes over to the other side ofthe point 3a. From this moment, the spring 4 acts to move the beam 3 andthe contact 2 quickly, so as to open the circuit.

The coil 9 has a main movable armature formed by a core ll adapted toslide about a push rod which bears on the beam 3 and the part l2 ofwhich is in contact with said beam and is made of non-magnetic material,whereas it part |2b is constructed of magnetic material, for example ofmild steel, and forms an auxiliary armature of the magnetic relay. Whena heavy overload occurs, for example a short-circuit, the armature Hmoves against the action of its weak retracting spring I3 until a rod[4, which is secured to said armature ll, abuts against the arm I0 andreleases the pawl l, releasing the contact 2 through the liberating meanhereinbefore described. The auxiliary armature 12b being directlyaffected by the magnetic flux which should cause the tripping, transmitsits impulse through the rod [2 to the beam 3 and imparts a considerableacceleration to the movable contact 2, as

soon as the latter is released by the liberating means, therebyproducing an extremely quick opening of the circuit. The main armaturell continues its travel and acts on the rod l2 through the intermediaryof the shoulder lZa, so as to add its impulse to that of the auxiliaryarmature l2b, thereby ensuring in particular the opening of the circuitif the movable contact 2 had a tendency to adhere to the movable contact6.

In Figure 1, upward movement of the armature reacts through spring [3 onrod [2 and tends to displace it. At first, however, stem 12 is held bylever 3 urged by spring 4, which i sufficient to enable the armature totravel the short distance required for actuating lever l and releasingcontact 2.

In the case of Figures 2 and '3, the current arrives by the terminal 29,passes through the fixed contacts 20, 2! which are short-circuited bythe movable contact bridge 22, passes through the coil 23 and thebimetallic strip 24, and passes out through the terminal 25. The bridge22 is supported by a movable rod, the part 26 of which is made ofinsulating material and is of larger diameter than the part 2'? whichforms the auxiliary armature of the magnetic relay. The free end of thepart 27 is pivoted on a two-armed pawl 28 which pivots at 29. Said pawlengages the nose of one of its arms in a pawl 30 pivoted on the fixedpivot 38, whereas the nose of the other end is held by a flap 32 which iheld by a light spring 320. against the stop 33. A spring 34 tends topush back the rod 21 and the contact 22 in the open circuit direction.The pawl 28 is pivoted at 29 to a connecting link 35 which is pivoted atits other end on a bell-crank lever 36 which can swing about the fixedpoint 31 and the other end of which is provided with an elongated slot38 in which is engaged a setting knob 39.

This knob is depressed in order to bring the circuit breaker back to thepositions shown in Figures 2 and 4 after disappearance of the currentdefects which had brought it to the positions shown in Figures 3 and 5.

In order to produce the release of the movable contact, it is necessaryto lift the pawl 30 so as to disengage the upper nose of the pawl 28,either by the action of the bimetallic strip 24, or by the efiect of themovement of the main armature 40 which is attracted towards the core 6|of the coil 23 compressing the retracting spring 42, and lifting thepawl 36 by means of a boss which is provided on said armature to act onthe end of the pawl resting against the armature it. The movable contactis thus released, since the rod 2126 can be moved towards the right,assisted by the spring .54, disengaging the pawl 28 from the flap 32.The auxiliary armature 2'! being also attracted towards the core M, ittransmits its impulse to the movable contact as soon as same has beenreleased by the main armature 40. Toward the end of its travel, saidarmature 4i] encounters the shoulder of the rod 26 and then actseffectively in the case in which the movable contact might have atendency to adhere to the fixed contacts. The connecting link 35 and thelever 36 have been displaced by the spring 43, so that the mechanism isin the position shown in Figure 3.

Figures 4 and show a modification of this construction. The spring M isreplaced by a spring M which bears on an abutment 45, and

.also on the pin 56 forming the articulation between the pawl 28 and therod 2?. The rod 21 slides in an opening of the pin 46. Suitable means isprovided for insuring a pressure between the contacts. In onearrangement this is done by a spring 4'! bearing on the pin 46, and alsoon a washer 48 which i held by a nut 49 on the rod 21.

According to the invention, the movable contact is advantageouslyconstructed in the form 'of a bridge 22 which is pivoted with limitedplay on the head 26a of the rod 26, and with a stiff fit on its pivot50. Owing to thi articulation, the pressure is balanced on the two fixedcontacts, when the circuit is closed, and owing to the stiff fit on thepivot 50, the movable contact retains, when the circuit i opened, theposition in which the separation of the contacts takes placesimultaneously at the contacts 20 and 2|, which has the effect ofproducing even wear of the contacts and of contributing to the speed ofthe break, in view of the fact that, from the start of the movement, thelength of the arc is double the displacement of the contact 22.

It is obvious that various modification can be made in the constructionof the apparatus without departing from the spirit of the invention.Thus, for example, the spring 32 (Figures 2 to 5), instead of bearing onthe core ll, could bear on a shoulder of the rod 26, so that all theenergy of the main armature 40 would be accumulated, from the beginningof its movement, for the purpose of its subsequent action on the movablecontact.

What I claim is:

1. An automatic circuit breaker comprising a fixed contact, a movablecontact, means normally resiliently urging the movable contact againstthe fixed contact, releasable spring-actuated means tending to open themovable contact, look-- ing means for restraining the spring actuatedmeans, an electromagnet through which the circuit current flows, anunlocking member operatively connected to said locking means, actuatingmeans responsive to said electro-magnet for actuating said unlockingmember and freeing the spring actuated means in response to a heavyoverload current flowing through said electromagnet, a principal movablearmature for cooperating with said electro-magnet under the action ofsaid overload current, a member directly operatively connected to themovable contact and provided with means arranged in the path of movementdescribed by the principal armature whereby the member is operated bysaid armature after the unlocking of the movable contact, and anauxiliary movable armature cooperating with the electro-magnet andoperatively connected to the said member for separately and directlyacting upon the movable contact as soon as the spring actuated means hasbeen released.

2. An automatic circuit breaker comprising a fixed contact, a movablecontact, means for normally holding closed the movable contact on thefixed contact, releasable means for displacing the movable contact inresponse to an overload in the circuit, an electromagnet through which acircuit current flows, said displacing means including an operatingmember connected to the movable contact, a main movable armatureactua'table by the electromagnet in response to a heavy overload andprovided with means for acting upon said member during the movement ofthe member, and an auxiliary armature, actuatable by the electromagnetin response to a heavy overload, separately and directly acting uponsaid member as soon as the displacing means has been released.

3. An automatic circuit breaker according to claim 2, includingconnections whereby the releasable means for displacing the movablecontact is operated by said main movable armature.

4. An automatic circuit breaker as claimed in claim 2 wherein saidauxiliary movable armature is constituted by a part of said operatingmember.

5. An automatic circuit breaker as claimed in claim 2 including a secondfixed contact, said movable contact being arranged to bridge said fixedcontacts, one of said fixed contacts being electrically connected tosaid electromagnet and the other to the circuit line, said movablecontact including a bridging member lightly, frictionally held againstrotation on said operating member.

6. An automatic circuit breaker comprising a fixed contact, a movablecontact, means for normally holding closed the movable contact on thefixed contact, releasable means for displacing the movable contact inresponse to an overload in the circuit, an electromagnet through whichthe current flows, said displacing means including an operating memberitself comprising a rod connected to and adapted to actuate said movablecontact, an abutment on said rod, a main movable armature actuatable bythe electromagnet in response to a heavy overload being slidably mountedon said rod and arranged to act on said abutment when attracted by saidelectromagnet after the release operation of said displacing means, andan auxiliary armature constituting a part of said rod and actuatable bythe electromagnet in response to a heavy overload, separately anddirectly acting upon said member as soon as the displacing means hasbeen released.

FRANCOIS JEAN MARIE THEUNISSEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

